Nutraceutical and Specialty Lipids and their Co-Products doc

In addition, the beneficial health effects and essen-tiality of long-chain omega-3 fatty acids such as eicosapentaenoic acid EPA, and docosahexaenoic acid DHA and that of omega-6 fatty a

Nutraceutical and Specialty Lipids and their Co-Products

NUTRACEUTICAL SCIENCE AND TECHNOLOGY

Series Editor

F EREIDOON S HAHIDI , P H D., FACS, FCIC, FCIFST, FIFT, FRSC

University Research Professor Department of Biochemistry Memorial University of Newfoundland

St John's, Newfoundland, Canada

1 Phytosterols as Functional Food Components and Nutraceuticals,

edited by Paresh C Dutta

2 Bioprocesses and Biotechnology for Functional Foods and Nutraceuticals,

edited by Jean-Richard Neeser and Bruce J German

3 Asian Functional Foods, John Shi, Chi-Tang Ho, and Fereidoon Shahidi

4 Nutraceutical Proteins and Peptides in Health and Disease,

edited by Yoshinori Mine and Fereidoon Shahidi

5 Nutraceutical and Specialty Lipids and their Co-Products,

edited by Fereidoon Shahidi

A CRC title, part of the Taylor & Francis imprint, a member of the Taylor & Francis Group, the academic division of T&F Informa plc.

Boca Raton London New York

Nutraceutical and Specialty Lipids and their Co-Products

Edited by Fereidoon Shahidi

Published in 2006 by

CRC Press

Taylor & Francis Group

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© 2006 by Taylor & Francis Group, LLC

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Neutraceutical lipids and co-products / edited by Fereidoon Shahidi

p cm (Neutraceutical science and technology ; 5) Includes bibliographical references and index.

Taylor & Francis Group

is the Academic Division of Informa plc.

Interest in food lipids has grown dramatically in recent years as a result of findings related to theirhealth effects Fats and oils have often been condemned because of their high energy value and due

to potential health problems associated with certain saturated fatty acids as well as trans fats.

However, lipids are important in that they provide essential fatty acids and fat-soluble vitamins aswell as flavor, texture, and mouthfeel to foods In addition, the beneficial health effects and essen-tiality of long-chain omega-3 fatty acids such as eicosapentaenoic acid (EPA), and docosahexaenoic

acid (DHA) and that of omega-6 fatty acids such as arachidonic acid (AA) and γ-linolenic acid

(GLA) have been recognized Recently, the role of EPA and/or DHA in heart health, mental health,and brain and retina development has been well documented In this connection, there has been asurge in the public interest and thus inclusion of these fatty acids into foods such as spreads, breadand cereal products, orange juice, and dairy products, among others In addition, novel sources ofedible oils with specific characteristics such as those of fruit seed oils, nut oils, algal oils, andmedium-chain fatty acids as well as diacylglycerols have been explored The role of minor compo-nents in fats and oils and their effects on oil stability have been acknowledged Minor componentssuch as phospholipids, tocopherols and tocotrienols, carotenoids, and sterols as well as phenoliccompounds may be procured from the oil or the leftover meal and used as nutraceuticals andfunctional food ingredients

It is the purpose of this book to present a comprehensive assessment of the current state of thechemistry, nutrition, and health aspects of specialty fats and oils and their co-products and toaddress stability issues and their potential application and delivery in functional foods and geriatricand other formulations This book provides valuable information for senior undergraduate and grad-uate students as well as scientists in academia, government laboratories, and industry I am indebted

to the participating authors for their hard work and dedication in providing a state-of-the-art tribution and for their authoritative views resulting from their latest investigations on differentaspects of nutraceutical lipids and co-products

con-Fereidoon Shahidi

Fereidoon Shahidi, Ph.D., FACS, FCIC, FCIFST, FIFT, FRSC, is a University Research Professor,

the highest academic level, in the Department of Biochemistry, Memorial University ofNewfoundland (MUN), Canada He is also cross-appointed to the Department of Biology, OceanSciences Centre, and the aquaculture program at MUN Dr Shahidi is the author of over 550 sci-entific papers and book chapters and has authored or edited over 40 books He has given over 350presentations at different scientific meetings and conferences His research has led to a number ofindustrial developments around the globe

Dr Shahidi’s current research interests include different areas of nutraceuticals and functionalfoods and particularly work on specialty and structured lipids, lipid oxidation, food phenolics, and

natural antioxidants, among others Dr Shahidi is the editor-in-chief of the Journal of Food Lipids,

an editor of Food Chemistry, and a member on the editorial boards of the Journal of Food Science,

Journal of Agricultural and Food Chemistry, International Journal of Food Properties, Journal of Food Science and Nutrition, and Current Food Science and Nutrition He is the editor of the sixth

edition of Bailey’s Industrial Oils and Fats in six volumes Dr Shahidi has been the recipient of

numerous awards, the latest of which was the Stephen S Chang Award from the Institute of FoodTechnologists (IFT) in 2005, for his outstanding contributions to food lipids and flavor chemistry,and was also recognized by IFT as a Fellow in 2005

Dr Shahidi is a founding member and a past chair of the Nutraceutical and Functional FoodDivision of IFT and a councilor of IFT He has also served in the past as chairs for the Agriculturaland Food Chemistry Division of the American Chemical Society (ACS) and the Lipid Oxidationand Quality of the American Oil Chemists’ Society (AOCS) Dr Shahidi served as a member ofthe Expert Advisory Panel of Health Canada on Standards of Evidence for Health Claims forFoods, the Standards Council of Canada on Fats and Oils, the Advisory Group of Agriculture andAgri-Food Canada on Plant Products, and the Nutraceutical Network of Canada He also served

as a member of the Washington-based Council of Agricultural Science and Technology onNutraceuticals

R.O Adlof

Food and Industrial Oil Research, National

Center for Agricultural

Utilization Research

Peoria, Illinois, USA

Scott Bloomer

Archer Daniels Midland Company

James R Randall Research Center

Decatur, Illinois, USA

Yaakob B Che Man

Department of Food Technology, Faculty

of Food Science and Technology

Universiti Putra Malaysia

Serdang, Selangor, Malaysia

Grace Chen

United States Department of Agriculture

Agricultural Research Service

Albany, California, USA

Hang Chen

Department of Food Science

Center for Advanced Food Technology

Rutgers University

New Brunswick, New Jersey, USA

Armand B Christophe

Department of Internal Medicine

Ghent University Hospital

Department of Food Science

Center for Advanced Food Technology

Rutgers University

New Brunswick, New Jersey, USA

Paul Fedec

POS Pilot Plant Corporation

Saskatoon, Saskatchewan, Canada

New Brunswick, New Jersey, USA

Masashi Hosokawa

Laboratory of Biofunctional MaterialChemistry

Hokkaido UniversityHakodate, Japan

Charlotte Jacobsen

Department of Seafood Research

Danish Institute for Fisheries Research

Lyngby, Denmark

J.W King

Food and Industrial Oil Research

National Center for Agricultural

Utilization Research

Peoria, Illinois, USA

Yong Li

Center for Enchancing Food to Protect Health

Lipid Chemistry and Molecular Biology

Laboratory

Purdue University

West Lafayette, Indiana, USA

Jiann-Tsyh Lin

United States Department of Agriculture

Agricultural Research Service

Albany, California, USA

G.R List

Food and Industrial Oil Research

National Center for Agricultural

Utilization Research

Peoria, Illinois, USA

and

Food Science and Technology Consultants

Germantown, Tennessee, USA

Hu Liu

School of Pharmacy

Memorial University of Newfoundland

St John’s, Newfoundland, Canada

Marina Abdul Manaf

Department of Food Technology

Faculty of Food Science and Technology

Universiti Putra Malaysia

Serdang, Selangor, Malaysia

Thomas A McKeon

United States Department of Agriculture

Agricultural Research Service

Albany, California, USA

H Miraliakbari

Department of Biochemistry

Memorial University of Newfoundland

St John’s, Newfoundland, Canada

Kumar D Mukherjee

Institute for Lipid ResearchFederal Research Centre for Nutrition and FoodMünster, Germany

Nina Skall Nielsen

Department of Seafood ResearchDanish Institute for Fisheries ResearchLyngby, Denmark

Frank T Orthoefer

Food Science and Technology ConsultantsGermantown, Tennessee, USA

Andreas M Papas

YASOO Health, Inc

Johnson City, Tennessee, USA

Robert D Reichert

Industrial Research Assistance Program

National Research Council of Canada

Ottawa, Ontario, Canada

Robert T Rosen

Department of Food Science

Center for Advanced Food Technology

Memorial University of Newfoundland

St John’s, Newfoundland, Canada

and

Martek Biosciences Corporation

Winchester, Kentucky, USA

Fereidoon Shahidi

Department of Biochemistry

Memorial University of Newfoundland

St John’s, Newfoundland, Canada

Yuji Shimada

Osaka Municipal Technical Research Institute

Osaka, Japan

Barry G Swanson

Food Science and Human Nutrition

Washington State University

Pullman, Washington, USA

Maike Timm-Heinrich

Department of Seafood ResearchDanish Institute for Fisheries ResearchLyngby, Denmark

St John’s, Newfoundland, Canada

Purdue UniversityWest Lafayette, Indiana, USA

Nikolaus Weber

Institute for Lipid ResearchFederal Research Centre for Nutrition and FoodMünster, Germany

Fereidoon Shahidi and S.P.J.N Senanayake

Yaakob B Che Man and Marina Abdul Manaf

Roman Przybylski

Liangli Yu, John W Parry, and Kequan Zhou

Frank D Gunstone

Fang Fang, Hang Chen, Chi-Tang Ho, and Robert T Rosen

Scott Bloomer

Thomas A McKeon, Charlotta Turner,Xiaohua He, Grace Chen, and Jiann-Tsyh Lin

9 Tree Nut Oils and Byproducts: Compositional Characteristics and

Fereidoon Shahidi and H Miraliakbari

Yao-wen Huang and Chung-yi Huang

Brent D Flickinger

Bruce A Watkins and Yong Li

13 Occurrence of Conjugated Fatty Acids in Aquatic and Terrestrial

Bhaskar Narayan, Masashi Hosokawa, and Kazuo Miyashita

Yasushi Endo, Si-Bum Park, and Kenshiro Fujimoto

Fereidoon Shahidi and H Miraliakbari

16 Single-Cell Oils as Sources of Nutraceutical and Specialty Lipids: Processing

S.P.J.N Senanayake and Jaouad Fichtali

Karlene S.T Mootoosingh and Dérick Rousseau

18 Lipid Emulsions for Total Parenteral Nutrition (TPN) Use and

Hu Liu and Lili Wang

Frank D Gunstone

Barry G Swanson

Charlotte Jacobsen, Maike Timm-Heinrich, and Nina Skall Nielsen

Yuji Shimada, Toshihiro Nagao, and Yomi Watanabe

23 Structure-Related Effects on Absorption and Metabolism

Armand B Christophe

Karen Schaich

G.R List, R.O Adlof, and J.W King

Vitamin E: A New Perspective

Andreas M Papas

Nikolaus Weber and Kumar D Mukherjee

Frank T Orthoefer and G.R List

29 Centrifugal Partition Chromatography (CPC) as a New Tool for

Udaya Wanasundara and Paul Fedec

Robert D Reichert

1.1 Introduction 2

1.2 Chemistry and Composition of Lipids 2

1.2.1 The Fatty Acids 2

1.2.2 Saturated Fatty Acids 2

1.2.3 Unsaturated Fatty Acids 3

1.2.4 Acylglycerols 4

1.2.5 Phospholipids 4

1.2.6 Fat-Soluble Vitamins and Tocopherols 7

1.2.7 Sterols 7

1.2.8 Waxes 7

1.2.9 Biochemistry and Metabolism of Short-Chain Fatty Acids (SCFAs) 8

1.2.10 Biochemistry and Metabolism of MCFAs 8

1.2.11 Biochemistry and Metabolism of Essential Fatty Acids (EFAs) 9

1.2.12 Eicosanoids 10

1.3 Major Sources of Nutraceutical and Specialty Lipids 11

1.3.1 Fish Oils 11

1.3.2 Seal Blubber Oil (SBO) 12

1.3.3 Borage, Evening Primrose, and Blackcurrant Oils 13

1.3.4 Concentration of n-3 Fatty Acids from Marine Oils 15

1.3.5 Application of Lipases in Synthesis of Specialty Lipids 16

1.3.6 Structured Lipids 16

1.3.6 Synthesis of Structured Lipids from Vegetable Oils and n-3 Fatty Acids 17

1.3.7 Synthesis of Structured Lipids from Marine Oils and Medium-Chain Fatty Acids 18

1.3.8 Synthesis of SBO-Based Structured Lipids 19

1.3.9 Low-Calorie Structured and Specialty Lipids 19

1.4 Low-Calorie Fat Substitutes 20

1.4.1 Olestra (Sucrose Polyester) 20

1.4.2 Simplesse 21

1.4.3 Sorbestrin (Sorbitol Polyester) 21

1.4.4 Esterified Propoxylated Glycerols (EPGs) 21

1.4.5 Paselli 22

1.4.6 N-Oil 22

References 22

Nutraceutical and Specialty Lipids

Fereidoon Shahidi and S.P.J.N Senanayake*

Department of Biochemistry, Memorial University of Newfoundland,

St John’s, Newfoundland, Canada

1

* Current address: Martek Biosciences Corporation, 555 Rolling Hills Lane, Winchester, Kentucky.

1

1.1 INTRODUCTION

Lipids are organic substances that are insoluble or sparingly soluble in water They are importantcomponents in determining the sensory attributes of foods Lipids contribute to mouthfeel andtextural properties in the foods They have several important biological functions, which include:(1) serving as structural components of membranes; (2) acting as storage and transport forms ofmetabolic fuel; (3) serving as the protective coating on the surface of many organisms; (4) acting

as carriers of fat-soluble vitamins A, D, E, and K and helping in their absorption; and (5) beinginvolved as cell-surface components concerned with cell recognition, species specificity, and tissueimmunity Ironically, overconsumption of lipids is associated with a number of diseases, namelyartherosclerosis, hypertension, and breast and colon cancer, and in the development of obesity.There are several classes of lipids, all having similar and specific characteristics due to the pres-ence of a major hydrocarbon portion in their molecules Over 80 to 85% of lipids are generally inthe form of triacylglycerols (TAGs) These are esters of glycerol and fatty acids The TAGs occur

in many different types, according to the identity and position of the three fatty acid components.Those with a single type of fatty acid in all three positions are called simple TAGs and are namedafter their fatty acid component However, in some cases the trivial names are more commonlyused An example of this is trioleylglycerol, which is usually referred to as triolein The TAGs withtwo or more different fatty acids are named by a more complex system

Lipids, and particularly TAGs, are integrated components of our diet and are a major source ofcaloric intake from foods The caloric value of lipids is much higher than other food componentsand about 2.25 times greater than that of proteins and carbohydrates While a certain amount of fat

in the diet is required for growth and maintenance of the body functions, excessive intake of lipidshas its own implications While our body can synthesize saturated and monoenoic acids, polyun-saturated fatty acids (PUFAs) must be provided in the diet Deficiency of linoleic acid and n-3 fattyacids results in dermatitis and a variety of other disease conditions The role of n-3 fatty acids inlowering of blood cholesterol level and other benefits has been appreciated The ratio of the intake

of linoleic to α-linolenic acid in our diet should be approximately 2 and our daily caloric intake

should have a contribution of 3.0 to 6.0% and 2.0 to 2.5% of each of these fatty acids, respectively

Fatty acids are divided into saturated and unsaturated groups, the latter being further subdivided intomonounsaturated and PUFAs The PUFAs are divided into main categories depending on the posi-tion of the first double bond in the fatty acid carbon chain from the methyl end group of the mole-cules and are called n-3, n-6, and n-9 families

Saturated fatty acids contain only single carbon–carbon bonds in the aliphatic chain and all otheravailable bonds are taken up by hydrogen atoms The most abundant saturated fatty acids in animaland plant tissues are straight-chain compounds with 14, 16, and 18 carbon atoms In general, satu-rated fats are solid at room temperature They are predominantly found in butter, margarine, short-

common nomenclature for some saturated fatty acids is given in Table 1.1

Fatty acids containing 4 to 14 carbon atoms occur in milk fat and in some vegetable oils.For example, cow’s milk fat contains butyric acid (4:0) at a level of 4% In addition, fatty acidscontaining 6 to 12 carbon atoms are also present in small quantities The short-chain fatty acids are

usually present in butter and in other milk fat-based products For example, the short-chain fattyacids from butyric to capric are characteristic of ruminant milk fat.

Tropical fruit oils, such as those from coconut and palm kernel, contain very high amounts(approximately 50%) of lauric acid (12:0) They also contain significant amounts of caprylic (8:0),capric (10:0), and myristic (14:0) acids Canola oil is another example of a lauric acid-rich oil.Palmitic acid (16:0) is the most widely occurring saturated fatty acid It is found in almost allvegetable oils, as well as in fish oils and body fat of land animals The common sources of palmiticacid include palm oil, cottonseed oil, as well as lard and tallow, among others

Stearic acid (18:0) is less common compared to palmitic acid However, it is a major nent of cocoa butter This fatty acid may be produced by hydrogenation of oleic, linoleic, andlinolenic acids Palmitic and stearic acids are employed in food and nonfood (personal hygieneproducts, cosmetics, surfactants, etc.) products

Unsaturated fatty acids contain carbon–carbon double bonds in the aliphatic chain In general, thesefats are soft at room temperature When the fatty acids contain one carbon–carbon double bond inthe molecule, it is called monounsaturated Monounsaturated fatty acids are synthesized within the

Oleic acid (18:1n-9) is the most common dietary monounsaturated fatty acid and

The common nomenclature for some unsaturated fatty acids is given

in Table 1.2

PUFAs contain two or more carbon–carbon double bonds The PUFAs are liquid at roomtemperature In general, they have low melting points and are susceptible to oxidation They arefound in grains, nuts, vegetables, and seafood (Table 1.3) The PUFAs of animal origin can becategorized into different families according to their derivation from specific biosynthetic precur-sors In each case, the families contain from two up to a maximum of six double bonds, separated

by methylene-interrupted groups and they have the same terminal structure Linoleic acid (LA;18:2n-6) is the most common fatty acid of this type This fatty acid is found in all vegetable fats and

is required for normal growth, reproduction, and health It is the most predominant PUFA in the

LA serves as a precursor or “parent” compound of n-6 family of fatty acids that isformed by desaturation and chain elongation, in which the terminal (n-6) structure is retained Thus,

LA can be metabolized into γ-linolenic acid (GLA; 18:3n-6), dihomo-γ-linolenic acid (DGLA;

20:3n-6), and arachidonic acid (AA; 20:4n-6) Of these, AA is particularly important as an essential

TABLE 1.1

Nomenclature of Some Common Saturated Fatty Acids

component of the membrane phospholipids and as a precursor of the eicosanoids GLA, an importantintermediate in the biosynthesis of AA from LA, is a constituent of certain seed oils and has been

a subject of intensive study α-Linolenic acid (ALA; 18:3n-3) is a precursor of n-3 family of fatty

acids It is found in appreciable amounts in green leaves, stems, and roots It is a major component

of flaxseed oil (45 to 60%) (Table 1.3) When ALA is absorbed into an animal body through thediet, it forms long-chain PUFAs with an n-3 terminal structure ALA can be metabolized into eicos-apentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) They have specialfunctions in the membrane phospholipids In addition, EPA is a precursor of a series of eicosanoids.The major sources of EPA and DHA are algal, fish, and other marine oils

Edible fats and oils are composed primarily of TAGs Partial acylglycerols, such as mono- and cylglycerols, may also be present as minor components The TAGs consist of a glycerol moiety,each hydroxyl group of which is esterified to a fatty acid These compounds are synthesized by

dia-enzyme systems in nature A stereospecific numbering (sn) system has been recognized to describe

various enantiomeric forms (e.g., different fatty acyl groups in each positions in the glycerol

group is shown to the left of carbon-2; the carbon atom above this becomes carbon-1 and that below

becomes carbon-3 (Figure 1.1) The prefix “sn” is placed before the stem name of the compound.

Partial acylglycerols, namely diacylglycerols (DAGs) and monoacylglycerols (MAGs), areimportant intermediates in the biosynthesis and catabolism of TAGs and other classes of lipids Forexample, 1,2-DAGs are important as intermediates in the biosynthesis of TAGs and other lipids.2-MAGs are formed as intermediates or end products of the enzymatic hydrolysis of TAGs TheDAGs are fatty acid diesters of glycerol while the MAGs are fatty acid monoesters of glycerol TheMAGs and DAGs are produced on a large scale for use as surface-active agents Acyl migration mayoccur with partial acylglycerols, especially on heating, in alcoholic solvents or when protonatedreagents are present

In phospholipids, one or more of the fatty acids in the TAG is replaced by phosphoric acid or itsderivatives Phospholipids are major constituents of cell membranes and thus regarded as structural

TABLE 1.2

Nomenclature of Some Common Unsaturated Fatty Acids

TABLE 1.3 Dietary Sources of Selected Fatty Acids

lipids in living organisms The acyl groups in phospholipids occur in the sn-1 and sn-2 positions of the glycerol moiety while a polar head group involving a phosphate is present in the sn-3 position

of the molecule There are several types of phospholipids (Figure 1.2) These are based on the phatidic acids (monoesters of the tribasic phosphoric acid), which themselves are diacyl derivatives

phos-of 3-glycerophosphoric acid The major types phos-of phospholipids include phosphatidylcholine (PC),phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI), and phos-phatidylglycerol (PG), among others

Phospholipids of various types are present as minor components (0.5 to 3.0%) in most crudeoils However, these compounds are mainly removed during the refining process They may berecovered as a distillate byproduct during deodorization and are generally referred to as lecithin,which is a mixture of phospholipids The major phospholipids in crude lecithin are usually PC, PE,

PI, and phosphatidic acids Lecithin is found in many sources of vegetable oils Commercial lecithin

is generally produced from soybean oil during the degumming process Lecithin is also availablefrom sunflower, rapeseed, and corn oils These are important surface-active compounds used exten-sively in the food, pharmaceutical, and cosmetic applications

The hydrolysis of phospholipids gives rise to various products For example, hydrolysis of PCoccurs with aqueous acids and the products are glycerol, fatty acids, phosphoric acid, and choline.However, enzyme-assisted hydrolysis is more selective and gives rise to a variety of products

FIGURE 1.2 Chemical structures of the major phospholipids.

Phospholipase A1causes deacylation at the sn-1 position, liberating fatty acids from this position

sn-2 position.

There are differences in the natural distribution of fatty acids associated with lipids such asphospholipids and TAGs For example, it is generally believed that phospholipids, such as lecithin

reported that phospholipids present

in marine species are generally unsaturated and esterified mainly with EPA and DHA Menzel and

studied PC and PE constituents of menhaden oil and found that their PUFAs were located

mainly in the sn-2 position of the TAG molecules The sn-2 position of PC in menhaden oil tained 29 and 42% EPA and DHA, respectively, whereas the sn-1 position contained only 1.7 and

con-12.5%, respectively, of these fatty acids However, the phospholipid content of refined, bleached,

, due to the removal of polar compounds during the degummingprocess

fatextraction procedure Silicic acid column chromatography with methanol after eluting neutral lipids

and

provide a means for separating individual phospholipids

Vitamins A and D are stored in large amounts in the liver of fish Therefore, fish liver oils areconsidered as exceptionally rich sources of vitamins A and D After vitamin A was synthesized andproduced commercially, production of the liver oils for vitamins A and D became a minor industry

in North America Vitamin E or α-tocopherols are also present in marine lipids Though present in

lower amounts, the tocopherols and tocotrienols attract attention because of their vitamin E andantioxidant properties The tocopherols are a series of benzopyranols with one, two, or three methylgroups attached to the phenolic ring The molecules also have a 16-carbon side chain moiety on thepyran ring In tocopherols the side chain is saturated, whereas in tocotrienols the side chain is unsat-

urated and contains three double bonds There are four tocopherols and tocotrienols designated α,

However, the antioxidant activity is generally in the reverse order (δ > γ > β > α) Thus, various

oils do not follow a similar sequence of vitamin E and antioxidant activity

Most vegetable oils contain 0.1 to 0.5% sterols They may exist as free sterols and esters with chain fatty acids Sitosterol is generally the major phytosterol, contributing 50 to 80% to the totalcontent of sterols Campesterol and stigmasterol may also be present in significant levels.Cholesterol is generally considered to be an animal sterol It is not present in plant systems at anysignificant level The sterol content of some fats and oils is given in Table 1.4

Waxes include a variety of long-chain compounds occurring in both plants and animals Theseare generally water-resistant materials made up of mixtures of fatty alcohols and their esters Theydiffer from the long-chain fatty acids in the TAG molecules These include compounds of highermolecular weight (up to 60 carbon atoms and beyond) and are frequently branched with one or moremethyl groups Even though they may be unsaturated they do not generally exhibit a methylene-interrupted unsaturation pattern Waxes find useful applications in the food, pharmaceutical, andcosmetic industries

1.2.9 B IOCHEMISTRY AND M ETABOLISM OF S HORT -C HAIN F ATTY A CIDS (SCFA S )

Short-chain fatty acids (SCFA) are saturated fatty acids with 2 to 4 carbon atoms This family offatty acids includes acetic acid (2:0), propionic acid (3:0), and butyric acid (4:0) They are com-monly referred to as the volatile fatty acids and are produced in the human gastrointestinal tract via

SCFAs are present in the diet in small amounts,for example acetic acid in vinegar and butyric acid in bovine milk and butter They may also be pre-

SCFAsare more easily absorbed in the stomach and provide fewer calories than MCFAs and LCFAs

In nutritional applications, there has been a growing interest in the use of SCFAs as an tive or additional source of energy to the medium- (MCFA) and long-chain fatty acid (LCFA) coun-terparts The SCFAs, acetic, propionic, and butyric acids, are easily hydrolyzed from a single TAG

These fatty acids go directly into the

portal vein for transport to the liver where they are broken down to acetate via β-oxidation The

acetate can then be metabolized for energy or use in new fatty acid synthesis

have shown that achemically synthesized diet containing 40% (w/w) of nonprotein as short-chain triacylglycerols(1:1, triacetin and tributyrin) maintained body weight, improved nitrogen balance and liver func-tion, and enhanced jejunal and colonic mucosal adaptation in rats after 60% distal small-intestineresection with cecectomy, when compared to short-intestine animals receiving a diet withoutsupplemental lipid calories from medium-chain triacylglycerol (MCT) SCFAs affect gastrointestinal

and increasing sodium and water absorption

lipids, was MCT MCT is an excellent source of MCFAs for production of structured and specialtylipids Pure MCTs have a caloric value of 8.3 calories per gram However, they do not provide

incorpo-rated into mucosal cells without hydrolysis and may readily be oxidized in the cell MCTs pass

TABLE 1.4 Sterol Content of Fats and Oils

directly into the portal vein and are readily oxidized in the liver to serve as an energy source Thus,

and are more susceptible to oxidation in

They may be directlyabsorbed by the intestinal mucosa with minimum pancreatic or biliary function They are trans-

rather than through the intestinallymphatics In addition, MCFAs are more rapidly oxidized to produce acetyl-CoA and ketone bodiesand are independent of carnitine for entry into the mitochondria

MCTs need to be used with LCTs to provide a balanced nutrition in enteral and parenteral ucts29,30

prod- In many medical foods, a mixture of MCTs and LCTs is used to provide both rapidlymetabolized and slowly metabolized fuel as well as essential fatty acids Clinical nutritionists havetaken advantage of MCTs’ simpler digestion to nourish individuals who cannot utilize LCTs Anyabnormality in the numerous enzymes or processes involved in the digestion of LCTs can causesymptoms of fat malabsorption Thus, patients with certain diseases have shown improvement when

MCTs are also increasingly utilized in the feeding of critically ill

or septic patients who presumably gain benefits in the setting of associated intestinal dysfunction.Further investigation should clarify potential roles for MCTs in patients with lipid disorders asso-ciated with lipoprotein lipase and carnitine deficiencies MCTs may be used in confectioneries and

MCTs have clinical cations in the treatment of fat malabsorption, maldigestion, obesity, and metabolic difficulties

The EFAs are PUFAs which means that they have two or more double bonds in their backbonestructure There are two groups of EFAs, the n-3 fatty acids and the n-6 fatty acids They aredefined by the position of the double bond in the molecule nearest to the methyl end of the chain

In the n-3 group of fatty acids it is between the third and fourth carbon atoms and in the n-6 group

of fatty acids it is between the sixth and seventh carbon atoms The parent compounds of the n-6and n-3 groups of fatty acids are LA and ALA, respectively LA and ALA are considered to beessential fatty acids for human health because humans cannot synthesize them and must obtainthem from the diet Within the body, these parent compounds are metabolized by a series of alter-nating desaturations (in which an extra double bond is inserted by removing two hydrogen atoms)and elongations (in which two carbon atoms are added) as shown in Figure 1.3 This requires aseries of special enzymes called desaturases and elongases It is believed that the enzymes metab-

The potential health benefits of n-3 fatty acids include reduced risk of cardiovascular disease,

stud-ies have linked the dietary intake of n-3 PUFAs in Greenland Eskimos to their lower incidence of

and development throughout the life cycle of humans and therefore should be included in thediet Fish and marine oils are rich sources of n-3 fatty acids, especially EPA and DHA Cod liver,menhaden, and sardine oils contain approximately 30% EPA and DHA

The n-6 fatty acids exhibit various physiological functions in the human body The main functions

of these fatty acids are related to their roles in the membrane structure and in the biosynthesis ofshort-lived derivatives (eicosanoids) which regulate many aspects of cellular activity The n-6 fattyacids are involved in maintaining the integrity of the water impermeability barrier of the skin Theyare also involved in the regulation of cholesterol transport in the body

GLA, a desaturation product of linoleic acid, has shown therapeutic benefits in a number ofdiseases, notably atopic eczema, cyclic mastalgia, premenstrual syndrome, cardiovascular disease,

milk GLA is found in oats, barley, and human milk GLA is also found in higher amounts in plant

seed oils such as those from borage, evening primrose, and blackcurrant Algae such as Spirulina

and various species of fungi also seem to be desirable sources of GLA

of the eicosanoid cascade include the prostaglandins, prostacyclins, thromboxanes, leukotrienes,and hydroxy fatty acids They play a major role in regulating the cell-to-cell communicationinvolved in cardiovascular, reproductive, respiratory, renal, endocrine, skin, nervous, and immunesystem actions Arachidonic acid is derived from linoleic acid, which gives rise to series-2prostaglandins, series-2 prostacyclins, series-2 thromboxanes, and series-4 leukotrienes Theseend products of n-6 fatty acid metabolism induce inflammation and immunosuppression.Prostanoids (collective name for prostaglandins, prostacyclins, thromboxanes) of series-1 andleukotrienes of series-3 are produced from DGLA When n-3 fatty acids are processed in theeicosanoid cascade, series-3 prostaglandins, series-3 prostacyclins, series-3 thromboxanes, andseries-5 leukotrienes are formed

FIGURE 1.3 Metabolic pathways of the omega-3 and omega-6 fatty acids.

The biological activities of the eicosanoids derived from n-3 fatty acids differ from thoseproduced from n-6 fatty acids For example, series-2 prostaglandins formed from AA may impairthe immune functions while series-3 prostaglandins produced from EPA ameliorate immunodys-

to 12-carbon monounsaturated fatty acids have been found in some fish oils The major n-3 PUFAsare generally 18:4, 20:5, and 22:6 The lipid of most common fish is 8 to12% EPA and 10 to 20%DHA The fatty acid composition of menhaden oil, as an example of a fish oil, is given in Table 1.5.Traditionally, fish oils have been used after a partial hydrogenation process This is essential ifthe oil is to be used as a component of fat spreads The process of partial hydrogenation provides amore desirable product with increased oxidative stability with a required melting behavior However,the nutritional value of the product is compromised During hydrogenation, n-3 PUFAs may be

converted to fatty acids with lower unsaturation with some double bonds of trans configuration.

TABLE 1.5 Fatty Acid Composition of Seal Blubber and Menhaden Oils

The n-3 PUFAs, especially EPA and DHA, present in fish and fish oils have an imputed majorpositive role in human health and disease It has been shown that n-3 PUFAs in fish oils have aninhibitory effect on platelet aggregation, and this reduces the risk of thrombosis, which is a major

Furthermore, the n-3 PUFAs in fish oils are very effective in

As aconsequence awareness of these possible beneficial effects, increased consumption of n-3 fattyacids in the form of either dietary fish or fish oil capsules is a recognized change in the nutritionalhabits of many individuals

PUFAs, especially those of the n-3 family The fatty acid composition of SBO is quite similar tothat of fish oils as it contains a large proportion of highly unsaturated fatty acids Table 1.5 sum-marizes the fatty acid profile of seal blubber and menhaden oils A comparison of the fatty acidcomposition of these oils indicated that menhaden oil had a higher amount of EPA and DHA thanSBO, but the latter had a higher content of docosapentaenoic acid (DPA, 4.7%) than fish oils, andcontained 6.4% EPA and 7.6% DHA

SBO and fish oils differ from one another in the dominance and distribution of fatty acids in theTAG molecules The n-3 fatty acids, such as EPA, DPA, and DHA, in SBO are mainly located in

the primary positions (sn-1 and sn-3) of TAG molecules Thus, the proportions in the sn-1 and

sn-3 positions were EPA, 8.4 and 11.2%; DPA, 4.0 and 8.2%; and DHA, 10.5 and 17.9%,

respec-tively However, in fish oils these fatty acids are preferentially esterified at the sn-2 position of the TAGs (17.5% EPA, 3.1% DPA, and 17.2% DHA) In the sn-2 position of SBO, EPA, DPA, and

liber-ated from the primary positions of TAGs via hydrolysis by pancreatic lipase The rate of hydrolysis

at the sn-2 position of TAGs is very slow, and as a result the fatty acids at this position remain intact

as 2-MAGs during digestion and absorption

Processing steps of SBO are similar to those of vegetable oils The basic processing stepsfor the manufacturing of SBO involve rendering to release the oil followed by degumming, alkalirefining, bleaching, and deodorization Each processing step has a specific function and may affectthe quality of the resultant oil by removing certain major and minor components During process-ing, impurities such as free fatty acids, mono- and diacylglycerols, phospholipids, sterols, vitamins,hydrocarbons, pigments, protein and their degradation products, suspended mucilagenous andcolloidal materials, and oxidation products are removed from the oil Heating may be required todenature the residual flesh proteins and to break the cell walls so that the oil and water can be

Refined oil is then heated and mixed with bleaching clay to remove various colored compounds aswell as phospholipids, metals, soap, and oxidation products This process is generally carried outunder vacuum to minimize oxidation Subsequently, the oil is deodorized in order to removeoff-odor volatiles

Different procedures may be explored for improving the oxidative stability of SBO Particularemphasis may be placed on the use of natural antioxidants, especially dechlorophyllized green tea

DGTE as well as individual tea catechins, namely epicatechin (EC), epigallocatechin (EGC), catechin gallate (ECG), and epigallocatechin gallate (EGCG), when added to SBO The potency of

epi-catechins in retarding oxidation of SBO was in the decreasing order of ECG > EGCE > EGC >

EC Therefore, DGTE and isolated tea catechins may be used as effective natural antioxidants for

stabilization of SBO tert-Butylhydroquinone (TBHQ), a synthetic antioxidant, was also highly

effective in retarding oxidation of SBO

Microencapsulation provides an alternative method for stabilization of edible oils, possiblytogether with the use of antioxidants Among the encapsulating materials tested for encapsulation

and hence stabilization of SBO, β-cyclodextrin was most effective and retained 89% of total PUFA

Changes in then-3 fatty acid content of stored SBO, both in the encapsulated and unencapsulated forms, have beendetermined (data not shown) The n-3 fatty acid content of unencapsulated SBO decreased by 50%

However, in β-cyclodextrin, the encapsulated SBO remained nearly unchanged even after 49 days

of storage The total PUFA content in β-cyclodextrin-encapsulated SBO decreased marginally after

49 days of storage while that for the control sample changed from 22.6 to 11.5% The progression

of peroxide values in unencapsulated and encapsulated SBO stored at room temperature has been

evaluated (data not shown) β-Cyclodextrin served better in controlling the formation of peroxides

than the control The peroxide value of control samples increased from 2.1 to 29.8 meq/kg oil over

49 days of storage The corresponding values for β-cyclodextrin-encapsulated oil were smaller,

changing from 3.0 to 10.2 meq/kg oil These results suggest that microencapsulation of SBO, usingstarch-based wall materials, improved the oxidative stability of the oil and preserved the integrity

of nutritionally important n-3 fatty acids

The major use of marine oils has traditionally been for the production of margarine and otheredible oil products following their hydrogenation Because of potential health benefits of unalteredPUFAs, incorporation of these fatty acids into the diet has shown promise for both food manufac-turers and nutritionists A wide variety of foods such as bread, baby foods, margarine, and salad

Microencapsulatedfish oil has been produced and may be used in health food formulations These products are inpowdered forms They can be incorporated mainly into milk powders, reduced fat products, fruit

SBO may be used in the manufacturing of theabove products Furthermore, this oil may also be used in infant formulas

Refined marine oils or their n-3 fatty acid concentrates have been used in pharmaceuticals such

as EPA and DHA capsules as well as skin and other personal care products For nutraceutical cations, SBO may be used in the form of a liquid, as soft gel capsules, or in the microencapsulatedform SBO may provide a very good starting material for preparation of n-3 fatty acid concentrates,

appli-as discussed earlier Marine oils have also been used for topical applications to treat various skindisorders

SBO may also lend itself to nonedible applications Oleochemicals (fatty acids, fatty alcohols,esters of alcohols, and nitrogen derivatives) derived from marine oils find a wide range of industrialapplications Marine oils may be used in the production of lubricants, corrosion inhibitors, textile,leather, and paper additives, cleaners, and personal care products Marine oils have been used as analternative fuel to petroleum-based products SBO has traditionally been used for industrial pur-poses It was used as a major fuel source for lighthouses in Newfoundland Other industrial uses ofmarine oils are in the production of polyurethane resins, cutting oils, printing ink formulations,insecticides, and leather treatment, among others

Borage (Borago officinalis L.) is an annual herbaceous plant and is commercially grown in North

America Borage oil (BO), extracted from seeds of the blue, star shaped borage flower, is attractingthe attention of alternative health practitioners and mainstream medicine alike for its profoundmedicinal properties Although the oil is getting all of the credit, it is actually the oil’s activecomponent, GLA, that has drawn the interest of researchers GLA is the first intermediate in the

bioconversion of LA to AA, and the first step of -6 desaturation (synthesis of GLA from LA) is

known to be rate limiting The seeds of borage contain approximately 38% oil with a GLA content

three times that in evening primrose seeds The oil is made up of 95.7% neutral lipids, 2.0%

glycolipids, and 2.3% phospholipids54 Neutral lipids of BO are composed of TAGs (99.1%), DAGs

The oil from evening primrose (Oenothera biennis L.) is another commercial source of GLA.

Evening primrose is a biennial plant and is a common weed that is native to North America.Interest in evening primrose oil (EPO) has intensified in recent years because of its GLA content.Although the evening primrose plant does not produce a high yield of seeds compared to thewell-known commercial oilseeds, it is preferred to other sources of GLA because it is easy toproduce and does not contain any ALA At present, EPO is the most important source of GLA,

available in over 30 countries as a nutritional supplement or as a constituent of specialty foods

In a number of countries, certain nutritional products require governmental registration beforethey can be marketed Several large organizations have been able to establish moderately large-scale extraction facilities for oils The EPO capsules contain 10 to 12% GLA and in Canada were

be more effective in some of its physiological effects than other oils in which GLA occurs Onepossible explanation is that GLA is present in EPO almost entirely as molecular species of TAG

com-ponents of EPO, not GLA, are responsible for some of the effects GLA from other oils(borage, blackcurrant, and fungal) may also be biologically less effective than that from EPO,partly because of the other fatty acids present and partly because of the different TAG structure

Blackcurrant is a perennial berry crop and is mainly cultivated in Europe and Asia Blackcurrant

acids, namely ALA (18:3n-3) and stearidonic acid (18:4n-3) Blackcurrant oil (BCO), having a GLA

uses of BCO, as in the case of borage and evening primrose, are generally based on claims

TABLE 1.6 Fatty Acid Composition of Borage, Evening Primrose, and Blackcurrant Oils

1.3.4 C ONCENTRATION OF n-3 F ATTY A CIDS FROM M ARINE O ILS

Several techniques have been explored for the concentration of PUFAs from marine oils Methodstraditionally employed for the concentration of PUFAs in oils make use of differences in physicaland chemical properties between saturated and unsaturated fatty acids For example, the meltingpoints of fatty acids are dependent on their degree of unsaturation EPA and DHA melt at –54 and

mixture of a saturated and unsaturated fatty acids decreases, the saturated fatty acids, having ahigher melting point, start to crystallize out first and the liquid phase becomes enriched in the unsat-urated fatty acids However, as the number and type of fatty acid components in the mixtureincreases, the crystallization process becomes more complex and repeated crystallization and sep-aration of fractions must be carried out to obtain purified fractions In the case of marine oils, notonly is there a very wide spectrum of fatty acids but the fatty acids exist, not in the FFA form, butesterified in TAGs However, the principle of low-temperature crystallization can still be applied to

subjected to low-temperature crystallization using solvents such as hexane and acetone in order toobtain n-3 fatty acid concentrates When SBO TAGs were dissolved in acetone, the total n-3 fattyacid content of the oil was increased to 48% at –70°C Meanwhile, when SBO was used in the FFAform, in the presence of hexane, the total n-3 fatty acid content was increased to 66.7% at –70°C.The ease of complexation of straight-chain saturated fatty acids with urea in comparison withPUFA is well established, and conventional urea complexation techniques using ethanol ormethanol as a solvent can be applied to the fatty acids of oils or their methyl or ethyl esters to pro-duce a fraction rich in PUFAs Initially, the TAGs of the oil are hydrolyzed into their constituentfatty acids via alkaline hydrolysis using alcoholic KOH or NaOH The resultant free fatty acids arethen mixed with ethanolic solution of urea for complex formation The saturated and monounsatu-rated fatty acids are readily complexed with urea and crystallize out on cooling and may be removed

by filtration The liquid fraction is enriched with n-3 fatty acids Urea complex formation of fatty

oil from 12 to 28% and 11 to 45%, respectively

Supercritical fluid extraction is a relatively novel technique which has found use in food andpharmaceutical applications The process makes use of the fact that at a combined temperature and

of gases are known to have good solvent properties at pressures above their critical values For food

environ-mentally acceptable, safe, readily available, and has a moderate critical temperature (31.1°C) andpressure (1070 psig) It separates fatty acids most effectively on the basis of chain length; hencethe method works best for oils with low levels of long-chain fatty acids Fish oils in the form of

concentrates of EPA and DHA The drawbacks of this method include the use of extremely highpressure and high capital costs

For the concentration of PUFAs on a large scale, each of the above physical and chemical aration methods has some disadvantages in terms of low yield, a requirement for large volumes ofsolvent or sophisticated equipment, a risk of structural changes in the fatty acid products, or high

their potential use for the enrichment of PUFAs in oils Lipases (EC 3.1.1.3) are enzymes that alyze the hydrolysis, esterification, interesterification, acidolysis, and alcoholysis reactions Thecommon feature among lipases is that they are activated by an interface Lipases have been used

cat-for many years to modify the structure and composition of foods Lipases that act on neutral lipids

.Use has been made of this relative substrate specificity to increase the concentration of n-3 PUFAs

in seal blubber and menhaden oils by subjecting them to hydrolysis by a number of microbial

Concentration of n-3 fatty acids by enzyme-assisted reactions involves mild reactionconditions and provides an alternative to the traditional concentration methods such as distillationand chromatographic separation Furthermore, concentration via enzymatic means may also producen-3 fatty acids in the acylglycerol form, which is nutritionally preferred

Enzymes have been used for production of nutraceutical lipids used for confectionery fat tions and nutritional applications Interesterification of high oleic (18:1) sunflower oil and stearic

formula-acid using immobilized Rhizomucor miehei lipase produces mainly1,3-distearoyl-2-monolein

(StOSt) Other reactants may also be used for production of specialty lipids useful as confectioneryfats In particular, there are many reports on enzymatic interesterification of mixtures of palm oilfractions and stearic acid or stearic acid esters to produce fats containing high concentrations of

compo-nents of cocoa butter, and enzymatic interesterification processes can produce fats with

The enzymes may also be used to synthesize a human milk fat substitute for use in infant

lipase as biocatalyst afforded TAGs derived entirely from vegetable oils rich in 2-position palmitate

with unsaturated fatty acyl groups in the sn-1 and sn-3 positions These TAGs closely mimic the fatty

acid distribution found in human milk fat, and when they are used in infant formulas instead of

con-ventional fats the presence of palmitate in the sn-2 position of the TAGs has been shown to improve

digestibility of the fat and absorption of other important nutrients such as calcium

The possible application of enzyme-assisted reactions for production of lower value cialty lipids such as margarine hardstocks and cooking oils has been investigated When nonspecific

nonspe-lipases such as those of Candida cylindraceae and C antarctica are used as biocatalysts for

esterification of oil blends, the TAG products are very similar to those obtained by chemical

similar products is technically feasible, although it has not been adopted on a commercial scale todate, largely because of the comparatively high process and catalyst costs

Enzymatic reactions can also be used for production of fats and oils containing nutritionallyimportant PUFAs, such as EPA and DHA For example, various vegetable and fish oils have been

structured lipids with MCFAs and PUFAs located specifically in either the sn-2 or sn-1,3 positions

of the TAG has been described Enzymatic processes are particularly suitable for the production andmodification of lipids containing PUFAs, because these unstable fatty acids are susceptible todamage under the more severe conditions used for chemical processing

Interesterification of blends of palm and hydrogenated canola oils and cottonseed and

hydro-genated soybean oils using sn-1,3-specific lipases as catalysts gave fats with a low trans fatty acid

lauric fats using immobilized Rhizomucor miehei as catalyst also produced fats that were functional

formu-lated without using hydrogenated fats

Structured lipids (SLs) are TAGs containing short- and/or medium- as well as long-chain fatty acidspreferably located in the same glycerol molecule They can be produced by chemical or enzymatic

processes and may be prepared as nutraceutical lipids for nutritional, pharmaceutical, and medicalapplications These TAGs have been modified by incorporation of desired fatty acids, or by chang-ing the fatty acid profiles from their native state in order to produce novel TAGs SLs are designedfor use as nutraceutical or functional lipids These specialty lipids may be synthesized via directesterification, acidolysis, alcoholysis, or interesterification reactions However, the common meth-ods reported in the literature for the synthesis of SLs are based on reactions between two TAG mol-ecules (interesterification) or between a TAG and an acid (acidolysis) These specialty lipids havebeen developed to optimize fully the benefit of various fatty acid moieties SLs have been reported

to have beneficial effects on a range of metabolic parameters including immune function, nitrogen

SLs are also synthesized to improve

or change the physical and/or chemical properties of TAGs Research on SLs remains an ing area that holds great promise for the future

interest-Nutraceutical is a term used to describe foods that provide health benefits beyond those ascribed

These products may be referred to as functional foods or tional lipids if they are incorporated into products that have the usual appearance of food, but to

SLs can be designed for use asmedical or functional foods as well as nutraceuticals, depending on the form of use

Lipids can be modified to incorporate specific fatty acids of interest in order to achieve desiredfunctionality SLs may be synthesized via the hydrolysis of fatty acyl groups from a mixture of

Various fatty acids are used

in this process, including different classes of saturated, monounsaturated, and n-3 and n-6 PUFAs,depending on the desired metabolic effect Thus, a mixture of fatty acids is incorporated onto thesame glycerol molecule SLs containing MCFAs and LCFAs have modified absorption ratesbecause MCFAs are rapidly oxidized for energy and LCFAs are oxidized very slowly SLs areexpected to be less toxic than physical mixtures of oils These specialty lipids are structurally andmetabolically different from the simple physical mixtures of MCTs and LCTs SLs containing

MCFAs at the sn-1,3 positions and LA at the sn-2 position may have beneficial effects both as an

SLs containing both GLA and n-3PUFAs may be of interest because of their desired health benefits We have successfully producedSLs containing GLA, EPA, and DHA in the same glycerol backbone using borage and evening

In this study, a number of commercially available enzymes,

namely lipases from Candida antarctica (Novozym-435), Mucor miehei (Lipozyme-IM), and

Pseudomonas sp (Lipase PS-30), were used as biocataysts with free EPA and DHA as acyl donors.

Higher incorporation of EPA + DHA (34.1%) in borage oil was obtained with Pseudomonas sp lipase, compared to 20.7 and 22.8% EPA + DHA, respectively, with Candida antarctica and Mucor

miehei lipases Similarly, in evening primrose oil Pseudomonas sp lipase gave the highest degree

of EPA + DHA incorporation (31.4%) followed by lipases from Mucor miehei (22.8%) and

Candida antarctica (17.0%) The modified borage and evening primrose oils thus obtained may

have potential health benefits

Recently, EPA and capric acid (10:0) have been incorporated into borage oil using two

immo-bilized lipases, SP435 from Candida antarctica and IM60 from Rhizomucor miehei, as

Higher incorporation of EPA (10.2%) and 10:0 (26.3%) was obtained with IM60 lipase,compared to 8.8 and 15.5%, respectively, with SP435 lipase

Huang and Akoh80 used immobilized lipases IM60 from Mucor miehei and SP435 from

Candida antarctica to modify the fatty acid composition of soybean oil by incorporation of n-3 fatty

acids The transesterification reaction was carried out with free fatty acid and ethyl esters of EPA

and DHA as acyl donors With free EPA as acyl donor, Mucor miehei lipase gave a higher poration of EPA than Candida antarctica lipase However, when ethyl esters of EPA and DHA were the acyl donors, Candida antarctica lipase gave a higher incorporation of EPA and DHA than

incor-Mucor miehei lipase.

EPA ethyl ester with an immobilized lipase from Candida antarctica The highest incorporation (31%) was obtained with 20% Candida antarctica lipase At a substrate mole ratio of 1:3, the ratio

the n-3 fatty acid content (up to 43%) of evening primrose oil with a corresponding increase in the

of groundnut oil by incorporating EPA and DHA using a sn-1,3-specific lipase from Mucor miehei

as the biocatalyst The modified groundnut oil had 9.5% EPA and 8.0% DHA

hydrolyzed borage oil using immobilized Candida rugosa lipase and then used this product with

n-3 fatty acids for the acidolysis reaction The total content of n-3 and n-6 fatty acids in erols was 72.8% following acidolysis The contents of GLA, EPA, and DHA in the SL so preparedwere 26.5, 19.8, and 18.1%, respectively The n-3/n-6 ratio increased from 0 to 1.09, following theacidolysis

from Mucor miehei and SP435 from Candida antarctica as biocatalysts Higher EPA

incorpora-tion was obtained using EPA ethyl ester than using EPA free fatty acid for both enzyme-catalyzedreactions

M EDIUM -C HAIN F ATTY A CIDS

Lipase-catalyzed acidolysis may be used to produce SLs containing MCFAs in the sn-1 and sn-3 positions We used an immobilized sn-1,3-specific lipase from Mucor miehei to incorporate capric

acid (10:0; a MCFA) into SBO containing EPA and DHA After modification, the fatty acid position of SBO was different from that of the unaltered oil Under optimum reaction conditions(500 mg oil, 331 mg capric acid, 45°C, 24 h, 1% water, 83.1 mg lipase, and 3 mL hexane), a SLcontaining 27.1% capric acid, 2.3% EPA, and 7.6% DHA was obtained Positional distribution of

com-fatty acids in the SL revealed that Mucor miehei lipase incorporated capric acid predominantly at the sn-1,3- positions of TAG molecules.

immo-bilized lipase from Rhizomucor miehei (IM 60) The fish oil (produced by Pronova Biocare Inc.,

Sandefjord, Norway) originally contained 40.9% EPA and 33.0% DHA After a 24 h incubation inhexane, there was an average of 43% incorporation of capric acid into fish oil, while EPA and DHA

incor-porate capric acid (10:0) and EPA into borage oil using lipase from Candida antarctica and

Rhizomucor miehei as biocatalysts Higher incorporation of EPA (10.2%) and 10:0 (26.3%) was

obtained with Rhizomucor miehei lipase, compared to 8.8 and 15.5%, respectively, with Candida

antarctica lipase.

Schizochytrium sp.) containing docosapentaenoic acid (DPA; 22:5n-6) and DHA and caprylic acid

(8:0) using lipases from Rhizomucor miehei and Pseudomonas sp The targeted products were

SL containing caprylic acid at the sn-1 and sn-3 positions and DHA or DPA at the sn-2 position of

glycerol When Pseudomonas sp was used, more than 60% of fatty acids in single-cell oil were exchanged with caprylic acid With Rhizomucor miehei lipase, the incorporation of caprylic acid

was only 23% Their results suggested that the difference in the degree of acidolysis by the twoenzymes were due to their different selectivity toward DPA and DHA as well as the difference intheir positional specificities

We have produced SLs via acidolysis of SBO and GLA (18:3n-6) with lipases PS-30 from

Pseudomonas sp and Lipozyme IM from Mucor miehei as the biocatalysts The highest

incorpora-tion of GLA (37%) into SBO was achieved with lipase PS-30 (data not shown) The modified SBO

EPA, and DHA (n-3 fatty acids) are produced and may have potential health benefits The oils taining both n-3 and n-6 fatty acids are considered important for specific clinical as well as nutri-tional applications

con-The fatty acid composition of SBO was also modified by incorporating a MCFA, capric acid

(10:0), using a sn-1,3-specific lipase from Mucor miehei The content of capric acid incorporated

into SBO was 25.4% Stereospecific analysis of modified oils revealed that capric acid was

prefer-entially esterified at the sn-1,3 positions of TAG of SBO Even though EPA (8.8%) and DHA (10.8%) were mainly located at sn-1,3 positions, sn-2 position also contained significant amounts

of these fatty acids (4.7% EPA and 4.1% DHA) Structured lipids containing n-3 PUFAs at the

sn-2 position and MCFAs at the sn-1,3 positions are expected to supply quick energy to individuals

with lipid malabsorption disorders and enhance the absorption of the n-3 PUFAs

The synthesis of low-calorie lipids, which are characterized by a combination of SCFAs and/orMCFAs and LCFAs in the same glycerol backbone, is an interesting area in the field of structuredand specialty lipids Interest in these types of products emerged from the fact that they contain 5 to

7 kcal/g caloric value compared to the 9 kcal/g of conventional fats and oils because of the lowercaloric content of SCFAs or MCFAs compared to their LCFA counterparts Reduced-calorie spe-cialty lipids are designed for use in baking chips, coatings, dips, and bakery and dairy products, or

as cocoa butter substitutes (Table 1.7) Currently, such products are synthesized by random cal interesterification between a short-chain TAGs (SCTs) and LCTs, typically a hydrogenated veg-

.Caprenin, composed of one molecule of a very long-chain saturated fatty acid, behenic acid

TABLE 1.7

Examples of Reduced-Calorie Lipids and Fat Replacers

Caprenin Capric, caprylic, behenic acids, and glycerol Confections; soft candies

Salatrim Soybean oil, canola oil Dairy products, baked goods, confections, margarine, spreads Olestra Sucrose core with 6 to 8 fatty acids Baked goods, fried foods, savory snacks, salad dressing Sorbestrin Sorbitol, methyl or ethyl esters of fatty acids Baked goods, fried foods

Simplesse Milk and/or egg/white proteins, pectin, Baked goods, ice cream, butter, sour cream, cheese, yogurt

sugar, citric acid

available reduced-calorie SL It provides 5 kcal/g90compared to 9 kcal/g of conventional fats andoils This product was originally produced by Procter and Gamble Company (Cincinnati, OH) Theconstituent fatty acids for caprenin synthesis are obtained from natural food sources For example,caprylic and capric acids are obtained by fractionation of palm kernel and coconut oils whilebehenic acid is produced from rapeseed oil Behenic acid, being a very long-chain saturated fattyacid, is poorly absorbed regardless of its position on the glycerol moiety The MCFAs provide fewercalories than absorbable LCFAs Caprenin reportedly has functional characteristics similar to cocoabutter and can be used as a cocoa butter substitute in selected confectionery products It is digested,

product at room temperature, has a bland taste, and is fairly heat stable The U.S Food and DrugAdministration (FDA) has received a Generally Recognized As Safe (GRAS) petition for capreninfor use in soft candy bars and in confectionery coatings for nuts, fruits, and cookies

Salatrim is also a reduced-calorie SL, which is composed of a mixture of very short-chain fatty

vegetable oils such as highly hydrogenated canola or soybean oil The very short-chain fatty acids

developed by Nabisco Foods Group (East Hanover, NJ) and is now marketed under the brand nameBenefat™ by Cultor Food Science, Inc (New York, NY) It has the taste, texture, and functional char-acteristics of conventional fats It can be produced to have different melting profiles by adjusting theamounts of SCFAs and LCFAs used in the chemical synthesis Reduced-fat baking chips are one of theproducts in the market that contain Salatrim and were introduced in 1995 by Hershey Food Corporation(Hershey, PA) Salatrim received FDA GRAS status in 1994 and can also be used as a cocoa butter sub-stitute It is intended for use in chocolate-flavored coatings, chips, caramel, fillings for confectionery

Neobee, another example of a low-calorie SL, is composed of capric and caprylic acids and duced by Stepan Company (Maywood, NJ) This class of specialty lipids includes different prod-

long-chain saturated fatty acid found in conventional butter oil and is suitable to replace butter oil in a

Consumers are demanding low-fat and even nonfat products with sensory qualities similar to those

of the regular products As a result, a number of fat substitutes have been developed

A slightly different carbohydrate-based approach is behind a lipid substitute known chemically as

Procter and Gamble Company (Cincinnati, OH) It is made by combining the disaccharide sucrosewith six to eight fatty acids via ester linkages, to produce large polymer molecules These fatty acidsare derived from vegetable oils such as soybean or corn oil It received FDA approval in 1996, based

on numerous studies concerning its safety and nutritional effects Olestra has been approved toreplace fully conventional lipids in the preparation of savory or salty snack foods such as chips andcrackers However, it is anticipated that in the future it will be used in salad dressings, shortening,table spreads, and dairy products

Olestra contains no available calories because the ester linkages hold the sucrose and fatty acidmolecules together in a way that cannot be broken down by digestive enzymes and therefore is not

The color,heat stability, and shelf-life stability of oil made with Olestra are comparable to those of conven-tional fat It has been extensively tested to determine its safety Olestra behaves in the mouth muchlike fat It travels undigested through the gastrointestinal tract without any of the energy locked up

in its structure being made available to the body Olestra is a fat-free and cholesterol-free substance,

is stable under ambient and high-temperature storage conditions, has acceptable flavor, and is

.One potential drawback of the consumption of Olestra is that it causes a decreased absorption offat-soluble vitamins Thus, vitamins A, D, E, and K have been added to Olestra to compensate this

It may also cause flatulence, abdominal cramping, diarrhea, increased bowl movement, reduceabsorption of cholesterol, and depletion of carotenoids

It is produced from milk

by a process of microparticulation During this process, proteins in solutionare deaerated and heated to a temperature just below the coagulation point of proteins The solutionwill then be homogenized and sheared at elevated temperatures Under heat and shear, the proteins

coagulate and shape into small spheroidal particles ranging in size from 0.1 to 2.0 µm The protein

aggregates are so small that the mouth cannot perceive them individually Once ingested, it isdigested and absorbed by the body as protein The final product provides the rich, creamy mouth-feel properties of fats and oils Simplesse cannot be used to cook foods because heat causes theprotein to gel and lose its creamy quality The U.S FDA approved the use of Simplesse in frozendesserts in 1990

This is a low-calorie, thermally stable, liquid lipid substitute composed of fatty acid esters ofsorbitol and sorbitol anhydrides Sorbestrin belongs to the family of carbohydrate-based fatty acidpolyesters Sorbitol and sorbitol anhydrides serve as the backbone of this compound, which is ester-ified with fatty acids of varying chain length and degree of saturation It has a caloric value ofapproximately 1.5 kcal/g and provides a bland oil-like taste Sorbestrin is suitable for use in allvegetable oil applications including fried foods, salad dressing, mayonnaise, and baked goods Itwas discovered in the late 1980s by Pfizer Inc (New York, NY) and is currently under development

by Danisco Cultor America Inc (Ardsley, NY)

EPGs are analogs of TAGs in which a propoxyl group has been introduced between the glycerolbackbone and the fatty acids to replace the ester linkage with an ether linkage Glycerol is firstreacted with propylene oxide to form a polyether glycol and then esterified with fatty acids to yield

an oil-like product These fatty acids may be obtained from edible oils such as lard, tallow, corn,canola, soybean, and cottonseed oils The physical properties of the finished product depend on the

type of fatty acids esterified EPGs are thermally stable It is manufactured by ARCO Chemical Co.(Newton Square, PA) and suitable for use in formulated products as well as baking and fryingapplications.

This product has been developed by Avebe America Inc (Princeton, NJ) It is a potato starch-based

kcal/g Under appropriate temperature conditions, this product forms a thermostable gel with asmooth, fat-like texture and neutral taste It has been used commercially in ice cream, puddings, andmeat products

and can partially or totally replace fats and oils in

It has been commercially available since 1984 and

is marketed by National Starch and Chemical Corp (Bridgewater, NJ) It has a caloric value of

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